O Sol e a Lua são os astros mais acessíveis à observação quer pelas suas frequentes aparições no céu, quer pelos seus tamanhos aparentes pronunciados. Por essas razões, constituem-se em astros disponíveis ao estudo, atendendo aos cuidados necessários no caso de observações solares. Apesar disso, pouca ou nenhuma atenção é dada a eles pelos professores dos ensinos fundamental e médio deixando de utilizar observações que podem contribuir muito para o aprendizado e, ainda, despertar o interesse dos alunos pela ciência. Em particular o Sol, permite a exemplificação e a compreensão de diversos fenômenos estudados na física, na biologia, na geografia, na química assim como permite aplicações práticas da matemática geometria e trigonometria ministradas em sala de aula. Escolhemos levar aos professores e aos estudantes universitários um curso sobre astronomia e física solar abordando questões sobre o Sol algumas pouco discutidas nos livros, mesmo os de Astronomia com a finalidade de proporcionar material de aprendizado, estudo e discussão de temas da astronomia moderna. Neste curso básico, serão abordados: como se concluiu que o Sol é uma estrela; como foram determinados seus principais parâmetros físicos e astronômicos tais como a sua distância, o seu tamanho, a sua massa, sua temperatura e composição química, e sua estrutura interna; e como o Sol produz energia. / The Moon and the Sun are the easiest celestial bodies to observe because their frequent appearance in the sky and their great apparent size. As a result, they are celestial bodies available to study, attending the essential cares regarding Sun observations. Nevertheless, teachers from elementary and high schools pay little or no attention to them and miss a great opportunity to use observations that might add a lot to the learning process and also to arouse students\' attention to science. The sun, specially, allows to illustrate and to understand several points that students learn in physics, biology, geography, and chemistry, and still can have practical applications in mathematics geometry and trigonometry taught in the classroom. We chose to bring to teachers and university students a course about astronomy and solar physics approaching issues of the Sun some of them very little discussed even in astronomy books for the purpose of provide learning material about modern astronomy topics. This basic course will develop: how was it concluded that the Sun is a star; how was it determined its main parameters, such as its distance, its size, its mass, its temperature and its chemical composition, and its internal structure; and how does the Sun produce energy.

Tendo em vista a Economia do Hidrogênio e sua infinidade de possibilidades, este trabalho estuda a geração de hidrogênio utilizando a energia solar fotovoltaica. Tendo em vista o consumo mundial de energia crescente, novos métodos de produção energética tem que ser levados em consideração, como o fato do hidrogênio ser um vetor energético de baixo impacto ambiental. Por outro lado, as reservas de combustíveis fósseis não serão capazes de satisfazer essa demanda em longo prazo e seu uso contínuo produz efeitos colaterais, como a poluição que ameaça a saúde humana e os gases de efeito estufa associados à mudança climática. No contexto do Brasil, a eletrólise da água combinada com as energias renováveis e células a combustível seriam uma boa base para melhorar o fornecimento de energia distribuída. Propõe-se, no presente trabalho, produzir hidrogênio por energia renovável, especificamente pelo acoplamento direto de um gerador fotovoltaico a um eletrolisador alcalino de água experimental, concebido localmente. Busca-se entender as características inerentes da interação desses dispositivos, encontrar as eficiências de cada etapa do sistema montado, assim como a eficiência global, adquirindo uma noção mais precisa e prática do uso da energia solar fotovoltaica na alimentação de um eletrolisador. Os resultados experimentais evidenciaram que a transferência da energia do gerador fotovoltaico ao eletrolisador depende fortemente das condições instantâneas climáticas e do modo como estes estão conectados. A interdependência entre variáveis foi reproduzida pelas investigações com destaque para: densidade de corrente no eletrolisador, potencial elétrico, irradiância solar, concentração do eletrólito, área do eletrodo e dimensões da célula eletrolítica. A eficiência do eletrolisador alcançada foi de 21%. A eficiência global (irradiância solar - hidrogênio) foi de 2%. O presente estudo dá subsídios para que seja dimensionado o acoplamento do sistema eletrolisador - gerador FV a partir de uma célula eletrolítica buscando-se minimizar perdas. / In view of the Hydrogen Economy and its endless possibilities, this work studies the hydrogen production using solar photovoltaic energy. With increasing global energy consumption, new methods of energy production have got to be taken into consideration, as hydrogen that it is an energy carrier with low environmental impact. On the other hand, fossil fuel reserves will not be able to meet this demand in the long term and its continuous use produces side effects such as pollution that threatens human health and greenhouse gases which are associated with climate change. For Brazilian energy context, electrolysis combined with renewable power source and fuel cell power generation would be a good basis to improve the distributed energy supply. It is proposed in this paper, to produce hydrogen by a direct coupling of a PV array with an experimental alkaline electrolyzer designed locally. It seeks to understand the inherent characteristics of the interaction of these energy forms, find the efficiencies of each step of the assembled system, as well as the global efficiency, acquiring a more precise notion and practice of the use of solar photovoltaic coupled with an electrolyzer. The experimental results showed that the transfer of energy from the PV array to the electrolyzer depends heavily on instant climatic conditions and how they are connected. The interdependence between variables was reproduced by the investigations, considering especially: current density, electric potential, solar irradiance, concentration of electrolyte, the electrode area and size of the electrolytic cell. The electrolyzer achieved an efficiency of 21%, approximately one-third of a commercial electrolyser efficiency. The overall efficiency (sol-hydrogen) was 2%. The present study gives subsidies to design an electrolyser PV generator system based on a given electrolytic cell seeking low losses.

銅銦鎵硒薄膜太陽能電池是一種清潔、環保的發電技術。 最近，銅銦鎵硒太陽能電池實現了20.9%的光電轉換效率，超出了多晶硅太陽能電池所保持的20.4%的薄膜太陽能電池的最高紀錄。 多種技術改進促成了這項薄膜太陽能電池的新紀錄。 其中一種重要改進是將1 到2 微米厚的硫化鎘硫化鋅混合窗口層替換成薄層硫化鎘和摻鋁氧化鋅透明導電層。 / 基於本實驗室在生長高質量銅銦鎵硒吸收層的先進技術，本工作重點研究了位於吸收層和透明窗口層之間的緩衝層和高阻窗口層。 這兩層的常規結構是由化學水浴法生長的硫化鎘層和本征氧化鋅層組成。 本論文的第一部分是關於這種常規結構的參數優化。 經過優化，本實驗室實現了在小型組件（總面積60 平方釐米）上15.6%的最高轉換效率。 / 本論文的第二部分關於用化學水浴法生長緩衝層。 我們發展了一種新型生長制備，用於避免氣泡和孔洞在吸收層表面的形成。 表面形貌測試結果顯示，使用此種設備生長的緩衝層能均勻的覆蓋銅銦鎵硒吸收層的表面。 其它硫化鎘的生長參數也根據新設備的特點進行了優化。 優化結果顯示，在空間電荷區的復合對電池轉換效率影響較大，而這種復合損失可以經過調整緩衝層與吸收能之間能帶結構得到減少。 我們研究了另外一種用化學水浴法生長的緩衝層：硫化鋅。 硫化鋅是一種無毒的寬禁帶材料，在短波部分有較少的光吸收。因此，它是一種很好的硫化鎘替代物。 我們研究了在不同生長溫度下的生長動力學機制。 最優的生長溫度是95 攝氏度。 經過生長結束後的退火過程，硫化鋅的禁帶寬度由3.61eV 下降到3.2eV。 再經過在氧氣環境中的退火，禁帶寬度可由3.2eV 繼續下降到2.9eV。 在單結電池中，硫化鋅的最優厚度在43 納米到62 納米之間。 在此厚度範圍中，具有硫化鋅緩衝層的電池實現了相對於具有硫化鎘緩衝層的電池更高的轉換效率。硫化鋅電池實現了與硫化鎘電池相近的開路電壓。 此項改進主要是由於在高溫條件下生長的硫化鋅與銅銦鎵硒層形成了更合適的能帶結構。 / 本論文的第三部分是關於用共濺射的方法生長鋅鎂氧化物緩衝層。 實驗結果顯示，鋅鎂氧化物的晶體結構和禁帶寬度與鎂含量相關。 當鎂含量小於0.4 時，鋅鎂氧化物具有(002)從優方位的纖鋅礦結構。 晶體質量隨鎂含量的增加而降低，同時，鋅鎂氧化物的禁帶寬度隨鎂含量的增加線性增加。 對於濺射方法生長的緩衝層，吸收層的表面鈍化對提高轉化效率非常重要。 / 本論文的最後一部分是關於高阻窗口層的研究。 相比於由本征氧化鋅構成的高阻窗口層，由鋅鎂氧化物構成的高阻窗口層能使電池有更優的穩定性。對於單結電池，本層的最優厚度是50 納米。對於小型組件，最優厚度在100 納米左右。 關於鎂的最優組分，結果仍爭議，但可以確定的是由較高濺射功率（大於2.2 瓦每平方釐米）產生的濺射損傷是應當盡量避免的。關於光照產生的亞穩定性的研究表明，亞穩定性強度與濺射環境中的氧氣含量正相關。 相對於無氧氣摻雜的電池，通過將1%的氧氣摻入氬氣濺射環境中，電池效率提高了0.5 個百分點。 / Cu(In,Ga)Se2 (CIGS)-based thin film solar cells have been regarded as a promising technology for cheap and environmentally friendly electricity generation. CIGS based solar cell has achieved 20.9% conversion effciency, while the offcial record for multicrystalline Silicon solar cell is 20.4%. A series of improvements have lead to this record for thin film based solar cell. An important improvement originated from the replacement of 1- to 2-um-thick doped (Cd,Zn)S layer by a thin, undoped CdS and a transparent conductive oxide(TCO). / Based on our techniques on growing high quality CIGS absorber layer, this work focuses on further optimization of buffer layer and high resistance window layer located between the CIGS absorber and the TCO window layer. The standard buffer structure includes a chemical-bath-deposited CdS layer and an intrinsic ZnO layer. The first part of this thesis is about optimization of this standard structure carried out in our laboratory. The best conversion effciency achieved on mini-module with total area of 60 cm² is 15.6 %. / The second part is about the fabrication of alternative buffer layers by chemical bath deposition. New deposition equipment has been invented to eliminate stationary bubbles and uncovered pinholes on absorber surface in the deposition of CBD CdS. Surface morphology studies shown that the buffer layer grown by this equipment has uniform coverage on the CIGS surface. Other deposition parameters in the chemical bath deposition of CdS buffer layer have been systematically studied employing this new equipment. Our results suggest that the detrimental effect of recombination in SCR region can be mitigated by proper band alignment in the buffer/absorber interface. / Another buffer layer grown by CBD method is ZnS. Because the wider bandgap and less light absorption in short wavelength range, ZnS is a good candidate to replace the toxic CdS buffer layer. The growth kinetics under different deposition temperature have been studied. The optimal temperature profile has been achieved by setting temperature at 95°C. The results of post annealing after deposition indicate that the bandgap energy of CBD ZnS decreases from 3.61 eV to 3.2 eV by annealing in vacuum. A further decrease from 3.2 eV to 2.9 eV could be caused by annealing with oxygen gas. The optimum thickness of ZnS used in single solar cells is between 43nm and 62nm. In this range, devices with CBD-ZnS buffer layer have achieved higher conversion effciency than CBD-CdS buffer layer solar cell. The open circuit voltage for ZnS-buffer devices has approached the value with CdS-buffer. The improvement is mainly due to proper band alignment of ZnS/CIGS interface achieved under high deposition temperature of CBD process. / The third part of this thesis is to study how to deposit (Zn,Mg)O buffer layers by co-sputtering method. It was found that the crystalline structure and optical bandgap of sputtered (Zn,Mg)O varies with Mg concentration. (Zn,Mg)O thin films with Mg concentration less than 0.4 have preferential orientation with a wurtzite phase (002). The crystal quality decreases with increasing Mg concentration and the band gap of the (Zn,Mg)O films has a linear relationship with the Mg concentration in this range. An interesting finding to emerge from this study is that oxygen passivation of absorber surface is critical to improve device performance with (Zn,Mg)O buffer layer deposited by sputtering method. / The last chapter assesses the effect of replacing high resistance window layer with (Zn,Mg)O in devices with CBD-ZnS buffer layer. Compared to devices with i-ZnO (high-resistance window) HRW layer, better device stability has been confirmed on solar cells with (Zn,Mg)O HRW layer. For single cells, the optimum thickness of HRW layer is about 50 nm, and the optimum thickness for mini-modules is around 100nm. Although no conclusion can be drawn with the optimum Mg concentration, the sputtering damage caused by sputtering power density higher than 2.2 W/cm² should be avoided. It was also shown that the metastability effect activated by illumination has positive correlation with the number of energetic oxygen ions in sputtering process. Compared to devices without oxygen doping, a higher effciency (increase of 0.5 % unit) has been achieved by the oxygen/argon doping ratio of 1 %. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhu, Jiakuan = 基於銅銦鎵硒薄膜太陽能電池的緩衝層結構研究 / 朱家寬. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 121-134). / Abstracts also in Chinese. / Zhu, Jiakuan = Ji yu tong yin jia xi bo mo tai yang neng dian chi de huan chong ceng jie gou yan jiu / Zhu Jiakuan.

by Sham Pong-kit. / Abstract also in Chinese / Bibliography: leaves 92-93 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1983

Thesis (M.Phil.)--Chinese University of Hong Kong. / Bibliography: leaves 211-214.

El uso de recursos renovables como fuente de generación de energía es un tema estudiado por el Grupo de Apoyo al Sector Rural PUCP, grupo al que va dirigido el presente proyecto. Este tipo de energía también es conocida como energía limpia ya que para su utilización no se produce emisión de gases contaminantes. Dentro de este tipo de energía, específicamente dentro de la energía solar térmica, se encuentra el reflector solar parabólico Scheffler, que aprovecha y concentra el calor que provee el Sol. Este tipo de reflector solar es utilizado en la cocina de alimentos en general y su uso en el Perú tiene un gran potencial debido a la intensa radiación presente en gran parte del país. El reflector solar parabólico Scheffler, al estar formado por un arreglo de espejos en toda su superficie, ve mermada su eficiencia debido a errores de inclinación al ensamblar dichos espejos. El objetivo del presente trabajo es desarrollar el diseño de un sistema que permita la detección de la inclinación los espejos que componen un reflector solar parabólico Scheffler de 8 m2 de área. Este sistema determina el error en la inclinación tanto en el eje horizontal como en el eje vertical de cada espejo, mediante técnicas de visión por computadora y de barrido láser. El documento se divide en 4 capítulos. El primero de ellos describe la problemática que será solucionada. En el segundo capítulo se presentan los requerimientos del sistema y se plantean los conceptos de solución. A continuación, y sobre la base del concepto óptimo de solución escogido, en el capítulo 3 se describe el desarrollo del sistema de detección de la inclinación de los espejos, así como sus componentes mecánicos, electrónicos y de control. En el cuarto capítulo se detalla el presupuesto requerido para implementar el sistema y, finalmente, se presentan las conclusiones que se obtienen del desarrollo del presente trabajo. / Tesis

Solar wind plasma is a turbulent medium, with processes that operate on many scales. Observations below proton scales are rare. Future spacecraft missions will have the required resolution to make these observations, so theoretical experiments and simulations at these scales will become increasingly important in order to match observations to theory. In this thesis, kinetic simulations are used to study electron dynamics within a turbulent electron-proton plasma. Firstly in this thesis, a study of the formation of electron temperature anisotropy due to magnetic reconnection is presented using particle in cell (PIC) simulations of the turbulent decay of sub-proton scale fluctuations. A fluctuation power spectrum with approximately power law form down to scales of order the electron gyroradius is formed. The signatures of collisionless reconnection within the turbulent field are generally associated with regions of strong parallel electron temperature anisotropy. Electrons from spatially different locations, can mix at reconnection sites, generating multi-peaked velocity distribution functions, which could become unstable to further instabilities. This is evidence of an important role for reconnection in the dissipation of small scale turbulent fluctuations. Secondly, a new type of electron scale vortex is discussed, which can spontaneously form during the simulations of turbulence. These are generated by electrons in (quasi) trapped orbits, which diamagnetically reduce the local magnetic field, creating a coherent structure. The properties of these vortices are categorized and compared to observations of similar structures called “magnetic holes” observed within the Earth’s plasma sheet. Finally, we look to understand what dissipation is in a collisionless plasma. We examine signatures of dissipation in the previous simulations, and in simulations where electrostatic electron-electron beam modes are generated within the turbulence.

Thesis. 1977. M.Arch.A.S.--Massachusetts Institute of Technology. Dept. of Architecture. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references. / by John I. Meyer, Jr. / M.Arch.A.S.

The performance of unheated solar buffer zones (SBZs) or sunspaces in relatively high latitudes' locations has become increasingly controversial. Conceived as simultaneously saving energy and providing amenity, the latter characteristic has provided the user with the opportunity and/or aspiration to negate the former - by heating a sunspace during winter either directly, or by opening it up as an extended heated part of the dwelling. Scotland has been host to passive solar projects promoting the use of small sunspaces where 'opening up' is a greater risk than directly heating. 'Opening-up' signals a change from 'indirect' to 'direct' solar gain with the heated volume partially extended. Within this context, this work examines the relevant aspects of a small sunspace as a passive solar technique by posing three questions from which answers are to be sought. 1. How useful and usable are the sunspaces ? 2. To what extent are occupants' interventions affecting energy saving ? 3. What is the energy 'worth' of the two sunspaces? The vehicle for this work is the CEC Solar Energy Demonstration Project at Easthall, Glasgow, where 36 thermally sub-standard flats built in the 1960s have been retrofitted with each flat having two sunspaces on opposite facades to tackle the issue of random orientation, and a common stairwell functioning as a shared thermal buffer space. The author's close acquaintanceship with a relatively large sample of occupants over a monitoring period of two years, taken in conjunction with data from questionnaires, interviews, diaries and personal observations, has enabled a substantive 'cause and effect' analysis. The findings confirm the likelihood of user intervention negating optimum performance, especially in spring and autumn, and in association with particular household types and characteristics. Nevertheless, the mean space heating load was approximately 30% lower than it would have been for the equivalent dwelling adjusted to the same internal temperature and ventilation rate, but without the front and rear sunspaces; and winter performance vindicates the role of sunspaces in providing good air quality at a relatively low running cost. The work sets aside the issue of life-cycle, pay-back analysis since, in general terms, this is dependent firstly on how much of the cost of sunspaces is written off as necessary floor area or improved amenity, and secondly on variable costs of a complementary energy-efficient package. However, on the assumption that these factors may be favourable, the work concludes with broad design recommendations based on the research findings; in particular recognising the dominance of the 'heat recovery' rather than 'solar' mode of operation of sunspaces.

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